The goal of the project is to increase knowledge of the chemical structures of glycoprotein hormones and relate the information gained to an understanding of their function in the body. The primary interest of the laboratory concerns two hormones, thyrotropin (TSH) and lutropin (LH), as well as related glycoproteins from both primate and non-primate mammalian species. Specific aims include determination of the disulfide bonding of both subunits of LH and TSH and investigation of three dimensional structure both by chemical and enzymic modifications and by a search for crystalline derivatives suitable for X-ray diffraction studies. Other major objectives are investigations of the contributions of various portions of the structures of TSH and LH (including carbohydrate) to their interactions with receptors and subsequent expression of hormonal activity, particularly by investigating the properties of active LH and TSH which are covalently cross-linked. It is hoped to make chemical modifications of TSH which will aid in the understanding of thyroid physiology and treatment of disorders of the thyroid gland and to prepare radiolabeled derivatives of TSH which allow optimal use of radioligand receptor assays for TSH and related substances.